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991.
Martín-Bravo S Meimberg H Luceño M Märkl W Valcárcel V Bräuchler C Vargas P Heubl G 《Molecular phylogenetics and evolution》2007,44(3):1105-1120
The Resedaceae, containing 6 genera and ca. 85 species, are widely distributed in the Old World, with a major center of species diversity in the Mediterranean basin. Phylogenetic analyses of ITS and plastid trnL-trnF sequences of 66 species from all genera of the Resedaceae reveal (1) monophyly of the family, in congruence with preliminary phylogenetic studies; (2) molecular support for the traditional morphological subdivision of the Resedaceae into three tribes according to ovary and placentation types, and carpel number; (3) two monophyletic genera (Caylusea, Sesamoides), and one natural group (core Reseda), which includes the remaining four genera of the family (Ochradenus, Oligomeris, Randonia, Reseda); (4) a monophyletic origin for four of the six taxonomic sections recognized within Reseda (Leucoreseda, Luteola, Glaucoreseda, Phyteuma). Our results lead us to interpret an increment of the basic chromosome number in the family from x=5 to x=6 in at least two independent instances, and a broad representation of polyploids in multiple lineages across phylogenies, including association between octoploids and alien invasion in many parts of the world. Species diversity, endemism number, phylogenetic relationships and sequence divergence in Resedaceae suggest two major centers of differentiation, one in the western Mediterranean, and the other in the eastern Mediterranean and SW Asia. Two independent colonization events to the Canary Islands from Africa are indicated for the two Canarian Reseda endemics. 相似文献
992.
993.
Bhaskara V Dupré A Lengsfeld B Hopkins BB Chan A Lee JH Zhang X Gautier J Zakian V Paull TT 《Molecular cell》2007,25(5):647-661
Mre11 and Rad50 are the catalytic components of a highly conserved DNA repair complex that functions in many aspects of DNA metabolism involving double-strand breaks. The ATPase domains in Rad50 are related to the ABC transporter family of ATPases, previously shown to share structural similarities with adenylate kinases. Here we demonstrate that Mre11/Rad50 complexes from three organisms catalyze the reversible adenylate kinase reaction in vitro. Mutation of the conserved signature motif reduces the adenylate kinase activity of Rad50 but does not reduce ATP hydrolysis. This mutant resembles a rad50 null strain with respect to meiosis and telomere maintenance in S. cerevisiae, correlating adenylate kinase activity with in vivo functions. An adenylate kinase inhibitor blocks Mre11/Rad50-dependent DNA tethering in vitro and in cell-free extracts, indicating that adenylate kinase activity by Mre11/Rad50 promotes DNA-DNA associations. We propose a model for Rad50 that incorporates both ATPase and adenylate kinase reactions as critical activities that regulate Rad50 functions. 相似文献
994.
Aleksi Lehikoinen Lluís Brotons John Calladine Tommaso Campedelli Virginia Escandell Jiri Flousek Christoph Grueneberg Fredrik Haas Sarah Harris Sergi Herrando Magne Husby Frederic Jiguet John Atle Kls ke Lindstrm Romain Lorrillire Blas Molina Clara Pladevall Gianpiero Calvi Thomas Sattler Hans Schmid Pivi M. Sirki Norbert Teufelbauer Sven Trautmann 《Global Change Biology》2019,25(2):577-588
Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south‐western (Iberia) and south‐central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (?7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant ?10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations. 相似文献
995.
Gaitán Juan J. Maestre Fernando T. Bran Donaldo E. Buono Gustavo G. Dougill Andrew J. García Martínez Guillermo Ferrante Daniela Guuroh Reginald T. Linstädter Anja Massara Virginia Thomas Andrew D. Oliva Gabriel E. 《Ecosystems》2019,22(7):1445-1456
Ecosystems - Drylands contain 25% of the world’s soil organic carbon (SOC), which is controlled by many factors, both abiotic and biotic. Thus, understanding how these factors control SOC... 相似文献
996.
997.
998.
Alba Casellas Cristina Mallol Ariana Salavert Veronica Jimenez Miquel Garcia Judith Agudo Mercè Obach Virginia Haurigot Laia Vilà Maria Molas Ricardo Lage Meritxell Morró Estefania Casana Jesús Ruberte Fatima Bosch 《The Journal of biological chemistry》2015,290(27):16772-16785
The human insulin-like growth factor 2 (IGF2) and insulin genes are located within the same genomic region. Although human genomic studies have demonstrated associations between diabetes and the insulin/IGF2 locus or the IGF2 mRNA-binding protein 2 (IGF2BP2), the role of IGF2 in diabetes pathogenesis is not fully understood. We previously described that transgenic mice overexpressing IGF2 specifically in β-cells (Tg-IGF2) develop a pre-diabetic state. Here, we characterized the effects of IGF2 on β-cell functionality. Overexpression of IGF2 led to β-cell dedifferentiation and endoplasmic reticulum stress causing islet dysfunction in vivo. Both adenovirus-mediated overexpression of IGF2 and treatment of adult wild-type islets with recombinant IGF2 in vitro further confirmed the direct implication of IGF2 on β-cell dysfunction. Treatment of Tg-IGF2 mice with subdiabetogenic doses of streptozotocin or crossing these mice with a transgenic model of islet lymphocytic infiltration promoted the development of overt diabetes, suggesting that IGF2 makes islets more susceptible to β-cell damage and immune attack. These results indicate that increased local levels of IGF2 in pancreatic islets may predispose to the onset of diabetes. This study unravels an unprecedented role of IGF2 on β-cells function. 相似文献
999.
Yu Shi Xingjia Xiang Congcong Shen Haiyan Chu Josh D. Neufeld Virginia K. Walker Paul Grogan 《Applied and environmental microbiology》2015,81(2):492-501
The Arctic is experiencing rapid vegetation changes, such as shrub and tree line expansion, due to climate warming, as well as increased wetland variability due to hydrological changes associated with permafrost thawing. These changes are of global concern because changes in vegetation may increase tundra soil biogeochemical processes that would significantly enhance atmospheric CO2 concentrations. Predicting the latter will at least partly depend on knowing the structure, functional activities, and distributions of soil microbes among the vegetation types across Arctic landscapes. Here we investigated the bacterial and microeukaryotic community structures in soils from the four principal low Arctic tundra vegetation types: wet sedge, birch hummock, tall birch, and dry heath. Sequencing of rRNA gene fragments indicated that the wet sedge and tall birch communities differed significantly from each other and from those associated with the other two dominant vegetation types. Distinct microbial communities were associated with soil pH, ammonium concentration, carbon/nitrogen (C/N) ratio, and moisture content. In soils with similar moisture contents and pHs (excluding wet sedge), bacterial, fungal, and total eukaryotic communities were correlated with the ammonium concentration, dissolved organic nitrogen (DON) content, and C/N ratio. Operational taxonomic unit (OTU) richness, Faith''s phylogenetic diversity, and the Shannon species-level index (H′) were generally lower in the tall birch soil than in soil from the other vegetation types, with pH being strongly correlated with bacterial richness and Faith''s phylogenetic diversity. Together, these results suggest that Arctic soil feedback responses to climate change will be vegetation specific not just because of distinctive substrates and environmental characteristics but also, potentially, because of inherent differences in microbial community structure. 相似文献
1000.
The Ever Changing Moods of Calmodulin: How Structural Plasticity Entails Transductional Adaptability
Alvaro Villarroel Maurizio Taglialatela Ganeko Bernardo-Seisdedos Alessandro Alaimo Jon Agirre Araitz Alberdi Carolina Gomis-Perez Maria Virginia Soldovieri Paolo Ambrosino Covadonga Malo Pilar Areso 《Journal of molecular biology》2014
The exceptional versatility of calmodulin (CaM) three-dimensional arrangement is reflected in the growing number of structural models of CaM/protein complexes currently available in the Protein Data Bank (PDB) database, revealing a great diversity of conformations, domain organization, and structural responses to Ca2 +. Understanding CaM binding is complicated by the diversity of target proteins sequences. Data mining of the structures shows that one face of each of the eight CaM helices can contribute to binding, with little overall difference between the Ca2 + loaded N- and C-lobes and a clear prevalence of the C-lobe low Ca2 + conditions. The structures reveal a remarkable variety of configurations where CaM binds its targets in a preferred orientation that can be reversed and where CaM rotates upon Ca2 + binding, suggesting a highly dynamic metastable relation between CaM and its targets. Recent advances in structure–function studies and the discovery of CaM mutations being responsible for human diseases, besides expanding the role of CaM in human pathophysiology, are opening new exciting avenues for the understanding of the how CaM decodes Ca2 +-dependent and Ca2 +-independent signals. 相似文献